Mixing mortar.



' 106. COMPOSITIONS,

COATING R PLASTIC.

UNITED STATES PATENT OFFICE.

EDMUND BECKER, OF WASHINGTON, DISTRICT OF COLUMBIA.

MIXING MORTAR.

1 2232351 Specification of Letters Patent. Patented Apr, 17, 1917,

No Drawing. Application filed February 24, 1912. Serial No. 679,730.

To all whom it may concem: plumbates are formed; the sea water thus Be it known that I, EDMUND BECKER, a adds to the durability of the cement instead citizen of the United States, residing at of impairing it. The presence of the lead Washington, District of Columbia, have insalts leads to similar results when the ce- 6o vented certain new and useful Improvement is exposed to certain acid vapors, as

ments in Mixing Mortars, of which the folsulfurous or hydrochloric acid vapors. lowing is a specification. Another advantage arises from the per- My invention relates to the common lime manency of the lead salts mentioned, since or cement mortars of the building trades; they have no tendency to absorb water of 65 10 that is, to any mixture of sand and water crystallization.

with lim r cement as sole active agent o'f There is this further point to be considthe mixture. The object of my invention is ered: Owing to the tendency of chemical reto protect such simple and standard mortar action to take place in that direction which against the well known slow destructive acinvolves the greatest fall in potential and 70 tion of certain chemicals that may accithe greatest permanency of the results, the

dentally be present in the mixture from the presence of the lead oxid is specially effecbeginning, or that may subsequently find tive in the neutralization of the acids to their way into the mixture from the surwhich the mortar would be exposed and rounding medium. which would tend to destroy it. 75 My experiments have proved the utility Sulfuric and hydrochloric acids, as above of adding to the mortarWeror other stated, have been recognized as the chief lead compounds, prefera y acetate. destructive agents of masonry; and their When Portland cement is mixe 1n accor noxious action is more rapid in sea water ance W1 1 my inven ion with water containthan in air. 5.: ing in solution acetate of lead an active Portland cement is of a very varied comchemical action ,takes place, as indicated by plex composition, but can be said to consist a relatively high increase in the temperature generally of strongly hydraulic active eleof the mass. The lead acetate is decomments in admixture with varying proporposed by any present acids as well as by tions of inert substances. These so-called 30 those soluble salts the acids of which cominert parts I have found to be the hurtful bine with lead protoxid' to form insoluble ingredients of Portland cement and my compounds. Sul urig and hydrochloric method has for its object to act on them and acids for inst-ance which areTzno'wh tofi'e' to transform them into truly inert or, better, fif a cal:.aeaac e sprewar. into useful p 35 if present, thereforef's rend themselvgs in Analysis of Portland cement shows that, decom osin the lead acea e"p"i'fidiice the besides the hydraulic cementing elements, "fiii'iha are samrau'ams, and the acetic there are found:

acid thus liberated transforms all the inert 1. An excess of free lime or calcium oxid; oxids into acetates which, being soluble, per- 2. Magnesia or magnesium oxid; e6, meate the whole mass and are intimately in- 3. An excess of alumina or aluminum corporated with and protected by the active oxid; crystals of the cement until their acetic acid 4. Oxid of iron is slowly but ultimately displaced and re- 5. Gypsum or calcium sulfate which isS placed by the carbonic acid of the air or the ground with the cement as a retarder to 45 water to be converted into permanent carmake it slow setting;

bonates. All of which, with the exception of iron Physically the addition of lead acetate to oxid, are more or less soluble in water; but the mortar produces an unctuous, plastic the iron oxid is readily attacked by the and more agglutinant paste which does not sulfuric and hydrochloric acids and changed 50 disintegrate, separate or wash apart when then into soluble sulfate and chlorid of iron. cast into the water, and which hardens as a When the Portland cement is mixed with solid and dense mass. the proper quantity of water, the active Moreover, when the cement containing a hydraulic cementing parts combine with lead oxid is exposed to the action of sulfates said water abandoning the excess of lime 55 and chlorids (which occur in sea water) under the form of hydrate of lime, the rapid insoluble sulfates and chlorids of lead and crystallization of which renders the cement quick-setting. A nick-setting cement being of difiicult or lmpossible use, a certain percentage of gypsum is ground with the cement to make it slow-setting.

But, as has been known for centuries, sulfate of lime is a hurtful addition to lime mortars, because it is soluble and has an afiinity for water; while keeping well in a dry atmosphere, it rots and disintegrates in water or humidity. Hence the quantity of gypsum in Portland cement has been reduced and limited to the lowest percentage possible, and it is highly detrimental for concrete in sea water.

It is the gypsum ground in as a retarder which furnishes the noxious sulfuric acid disclosed in the analysis of Portland cement.

The afiinity of magnesia for water being less than that of lime, it is apt to hydrate and swell subsequently to the setting of the mortar.

The above mentioned inert parts being mostly specifically lighter than the cementing parts will ascend and, united by molecular afiinity, will gather on top of the mortar or concrete and produce what is called the Laitance, the cementing properties of which are nil. On surfaces of concrete they show when wet and are called water-marks and are in reality incipient cracks. It is through these water-marks and the joints of masonry that the water exudes, loaded with the soluble inert parts, which carbonize into unsightly efilorescences or whitewash. These exudations leave in the mass of the concrete voids which add to the porosity of and impair the quality of the concrete.

The sulfuric acid and the hydrochloric acid, free or in combination reacting on the lead compounds, form insoluble combinations of anhydrous and stable sulfate and chlorid of lead which serve to render the concrete impervious and inattackable by the acids.

All previous efforts to produce a concrete which can stand in sea water have failed because they did not suppress the causes of decay inherent in the nature of Portland cement. All so-called waterproofing processes are ineffectual attempts at pore filling and do not act permanently. It is only by availing ones self of the reater afiinity of the acids in sea water to orm insoluble, anhydrous, permanent combinations with the lead components that the solution of the problem can be reached.

I am aware that the addition of acetate of lead to lime or cement mortars has been proposed by Hartnell, in British Patent 8,413 of 1890; also by Bouvier, in British Patent 16,232 of 1888; but the acetate of lead in each of these patents is used in combination with a relatively large proportion of sulfuric acid that enters into violent chemical combination with the lead acetate, virtually destroying it as such.

I am aware that the addition of acetate of lead has also been proposed by Guelick in U. S. Patent 410,688 of 1889, but Guelick uses an infinitesimal part not exceeding one part of'acetate in nearly nine thousand (8910) parts of the cement used; and this small fraction enters into combination with his added alum and borax, so that any preservative function such as contemplated in my mortar is absolutely out of question. In my mortar the acetate is used without any other ingredients and it must enter in the proportion of one part of acetate to two hundred parts of lime or cement to be capable of its intended operation.

I claim as my invention:

1. In the process of forming mortars, the step which consists in adding, during the mixing operation, and to the three common basic ingredients of mortar, to wit: (1) lime or cement, (2) water (3) sand; as preservative, a fourth ingredient consisting of a soluble salt of lead, which is adapted to form insoluble salts of lead, with mortar destroying agents; such soluble salt being present in a proportion which exceeds, by weight, one part in two hundred of the lime or cement that is used as sole active agent in the mixture.

2. In the process of forming mortars, the

step which consists in adding, during the mixture.

EDMUND BECKER. Witnesses:

A. M. PARKINS,

CAMILLE HINDMARSH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Iatents,

Washington, D. 0." 

